I think swaged is the correct term, and is used say on the ends of conduit tubing to allow one tube to be inserted in the next without using couplings.

I'm not quite sure why that would have been needed to be done at that particular spot. Several of the lugs had to be made specifically for this bike, including the bottom bracket lug without a seat tube connection.

Standard tubing sizes, of course, vary between tubes. Perhaps someone ordered custom made lugs the wrong size